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Posted: Wed Nov 09, 2016 9:55 pm
Dear Dr. Bach
At todays visit you talked about pneumothorax when air stacking I believe. As you remember this concerned me. My question to you now is on my sons vent his Tidal volume is set at 1250. Is that too high and why is it that high? He uses the same setting during the day via mouth and air stacking and with his mask while sleeping. He has the LTV 950. His settings are:
Breath rate:12 at night and 3 during the day.
Tidal volume: 1250
During the night its on pressure and during the day its on volume
With these setting do I need to worry and again is the Tidal Volume too high?
Posted: Thu Nov 10, 2016 2:26 pm
It is that high so that he can take all or part of the volume to vary his tidal volumes. Normally he should be able to take a breath to 3500 ml. The same settings can be good day and night because his brain can controls the air he gets whether awake or asleep. but he uses pressure preset during sleep. None of our patients have ever had a pneumothorax despite air stacking to pressures of 90 cm H2O 3x/day for in many cases over 50 years.
Posted: Thu Nov 10, 2016 3:54 pm
So I don't need to worry with the settings you have set for Johnny?
Posted: Thu Nov 10, 2016 4:01 pm
Michelle, you can always find something to worry about but these settings are necessary for John. Anytime you want to reduce them, go away but when John complains, he will be right. JB
Posted: Thu Nov 10, 2016 5:33 pm
So the settings that you have him on now can cause pneumothorax?
Posted: Thu Nov 10, 2016 8:33 pm
Michelle, I told you when you were here on Wednesday that no pressure at all can result in a pneumothorax. I think that you forgot.
Posted: Thu Nov 10, 2016 9:57 pm
Ok but my questions are is his settings a problem? Should they be lower or leave them alone because they are unlikely to cause a pneumothorax? I read up on it so I know what it is. I need you to tell me if by using his vent for air stacking and breathing at the numbers you have set them at are good and will unlikely cause it. He has been using the vent for 4 years and has not had a problem so I don't know why you brought it up. Now you have concerned me.
Posted: Fri Nov 11, 2016 8:34 am
Michelle, as I told you the settings are not the problem. He takes as much of the air as he feels that he needs and no more. The problem is the weight. The more he weighs the more pressure is necessary to ventilate the lungs. That is what you should be worried about.
Posted: Fri Nov 11, 2016 1:12 pm
The weight cant be change as we discussed. He does not eat much and its all he has left. Until someone can tell me what his decline would be if I reduced the steroids, he doesn't want to lower them. Its funny too that I know thin men with DMD who don't have good vital capacity either, so his weight as you say is not only the problem just a piece of the puzzle. So thank you for finally answering the question. I will leave his settings the way they are set. I will have him take in more air slowly to inflate the lungs, not with more force. Michelle